A back contact type solar cell element is conventionally known as one type of solar cell element (refer to, for example, Japanese Laid-Open Patent Publication No. 63-211773 (Patent Document 1) and Japanese Published Patent Publication No. 2002-500825 (Patent Document 2)).
The conventional solar cell element includes a semiconductor substrate exhibiting one conductivity type, a opposite conductivity type layer exhibiting a conductivity type opposite to the semiconductor substrate, a first electrode, and a second electrode having a polarity different from the first electrode. The semiconductor substrate has a plurality of through holes penetrating between a light receiving surface and a back surface. The opposite conductivity type layer includes a first opposite conductivity type layer arranged on the light receiving surface of the semiconductor substrate, second opposite conductivity type layers arranged on the surfaces of the through holes of the semiconductor substrate, and a third opposite conductivity type layer arranged on the back surface side of the semiconductor substrate. The first electrode includes a light receiving surface electrode part formed on the light receiving surface side of the semiconductor substrate, through hole electrode parts formed in the through holes, a bus bar electrode part formed at the ends of the back surface of the semiconductor substrate and a finger electrode part formed on the back surface of the semiconductor substrate. The light receiving surface electrode part, the through hole electrode parts, the finger electrode part, and the bus bar electrode part are electrically connected. The second electrode is formed at a portion of the back surface of the semiconductor substrate where the third opposite conductivity type layer is not formed.
The conventional solar cell module has a configuration in which the bus bar electrodes of a plurality of solar cell elements, each having the above configuration, are connected by wiring.
While wide spread use of the solar cell module using such a solar cell element is further being expected, it is essential to enhance the conversion efficiency of solar light with a simple configuration. It is important to reduce the loss of photovoltaic power in enhancing the conversion efficiency.